engine

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Published: Jul 21, 2018 License: BSD-2-Clause

README

G3N Banner

Godoc Go Report Card

G3N - Go 3D Game Engine

G3N (pronounced "gen") is an OpenGL 3D game engine written in Go. G3N was heavily inspired by three.js.

To see G3N in action try the G3N demo or the Gokoban award winning game.

G3ND In Action

Highlighted Projects

Gokoban - 3D Puzzle Game (1st place in the 2017 Gopher Game Jam)

Dependencies

G3N requires Go 1.8+

The engine needs an OpenGL driver installed in the system and on Unix like systems depends on some C libraries that can be installed using the distribution package manager. In all cases it is necessary to have a gcc compatible C compiler installed.

  • For Ubuntu/Debian-like Linux distributions, install the following packages:
    • xorg-dev
    • libgl1-mesa-dev
    • libopenal1
    • libopenal-dev
    • libvorbis0a
    • libvorbis-dev
    • libvorbisfile3
  • For CentOS/Fedora-like Linux distributions, install the following packages:
    • xorg-x11-devel.x86_64
    • mesa-libGL.x86_64
    • mesa-libGL-devel.x86_64
    • openal-soft.x86_64
    • openal-soft-devel.x86_64
    • libvorbis.x86_64
    • libvorbis-devel.x86_64
  • For Windows the necessary audio libraries sources and dlls are supplied but they need to be installed manually. Please see Audio libraries for Windows for details. We tested the Windows build using the mingw-w64 toolchain.
  • (Not fully-tested on OSX) On OSX, you should install the development files of OpenAL and Vorbis. If your are using Homebrew as your package manager, run: brew install libvorbis openal-soft

Installation

The following command will download the engine and all its dependencies, compile and install the packages. Make sure your GOPATH is set correctly.

go get -u github.com/g3n/engine/...

Features

  • Hierarchical scene graph. Any node can contain other nodes.
  • Supports perspective and orthographic cameras. The camera can be controlled by the orbit control which allow zooming, rotation and panning using the mouse or keyboard.
  • Suports ambient, directional, point and spot lights. Many lights can be added to the scene.
  • Generators for primitive geometries such as: lines, box, sphere, cylinder and torus.
  • Geometries can support multimaterials.
  • Image textures can loaded from GIF, PNG or JPEG files and applied to materials.
  • Loaders for the following 3D formats: Obj and Collada
  • Text support allowing loading freetype fonts.
  • Basic GUI supporting the widgets: label, image, button, checkbox, radiobutton, edit, scrollbar, slider, splitter, list, dropdown, tree, folder, window and layout managers (horizontal box, vertical box, grid, dock)
  • Spatial audio support allowing playing sound from wave or Ogg Vorbis files.
  • Users' applications can use their own vertex and fragment shaders.

G3N Banner

Basic application

The following code shows a basic G3N application (hellog3n) which shows a wireframed sphere rotating. You can install hellog3n using: go get -u github.com/g3n/demos/hellog3n

For more complex demos please see the G3N demo program.

package main

import (
	"github.com/g3n/engine/camera"
	"github.com/g3n/engine/core"
	"github.com/g3n/engine/geometry"
	"github.com/g3n/engine/gls"
	"github.com/g3n/engine/graphic"
	"github.com/g3n/engine/light"
	"github.com/g3n/engine/material"
	"github.com/g3n/engine/math32"
	"github.com/g3n/engine/renderer"
	"github.com/g3n/engine/window"
	"math"
	"runtime"
)

func main() {

	// Creates window and OpenGL context
	wmgr, err := window.Manager("glfw")
	if err != nil {
		panic(err)
	}
	win, err := wmgr.CreateWindow(800, 600, "Hello G3N", false)
	if err != nil {
		panic(err)
	}

	// OpenGL functions must be executed in the same thread where
	// the context was created (by CreateWindow())
	runtime.LockOSThread()

	// Create OpenGL state
	gs, err := gls.New()
	if err != nil {
		panic(err)
	}

	// Sets the OpenGL viewport size the same as the window size
	// This normally should be updated if the window is resized.
	width, height := win.Size()
	gs.Viewport(0, 0, int32(width), int32(height))

	// Creates scene for 3D objects
	scene := core.NewNode()

	// Adds white ambient light to the scene
	ambLight := light.NewAmbient(&math32.Color{1.0, 1.0, 1.0}, 0.5)
	scene.Add(ambLight)

	// Adds a perspective camera to the scene
	// The camera aspect ratio should be updated if the window is resized.
	aspect := float32(width) / float32(height)
	camera := camera.NewPerspective(65, aspect, 0.01, 1000)
	camera.SetPosition(0, 0, 5)

	// Add an axis helper to the scene
	axis := graphic.NewAxisHelper(2)
	scene.Add(axis)

	// Creates a wireframe sphere positioned at the center of the scene
	geom := geometry.NewSphere(2, 16, 16, 0, math.Pi*2, 0, math.Pi)
	mat := material.NewStandard(math32.NewColor("White"))
	mat.SetSide(material.SideDouble)
	mat.SetWireframe(true)
	sphere := graphic.NewMesh(geom, mat)
	scene.Add(sphere)

	// Creates a renderer and adds default shaders
	rend := renderer.NewRenderer(gs)
	err = rend.AddDefaultShaders()
	if err != nil {
		panic(err)
	}
	rend.SetScene(scene)

	// Sets window background color
	gs.ClearColor(0, 0, 0, 1.0)

	// Render loop
	for !win.ShouldClose() {

		// Rotates the sphere a bit around the Z axis (up)
		sphere.AddRotationY(0.005)

		// Render the scene using the specified camera
		rend.Render(camera)

		// Update window and checks for I/O events
		win.SwapBuffers()
		wmgr.PollEvents()
	}
}

hellog3n Screenshot

To Do

G3N is a basic game engine. There is a lot of things to do. We will soon insert here a list of the most important missing features.

Documentation

For the engine API reference, please use GoDoc. Currently the best way to learn how to use the engine is to see the source code of the demos from G3ND. We intend to write in the future documentation topics to build a user guide in the wiki.

Contributing

If you spot a bug or create a new feature you are encouraged to send pull requests.

Community

Join our channel on Gophers Slack (Click here to register for Gophers Slack).

Directories

Path Synopsis
Package animation
Package animation
Package audio contains sub packages for binding to external audio libraries and implements a spatial audio player.
Package audio contains sub packages for binding to external audio libraries and implements a spatial audio player.
al
Package al implements the Go bindings of a subset of the functions of the OpenAL C library.
Package al implements the Go bindings of a subset of the functions of the OpenAL C library.
ov
Package ov implements the Go bindings of a subset of the functions of the Ogg Vorbis File C library.
Package ov implements the Go bindings of a subset of the functions of the Ogg Vorbis File C library.
vorbis
Package vorbis implements the Go bindings of a subset (only one function) of the functions of the libvorbis library See API reference at: https://xiph.org/vorbis/doc/libvorbis/reference.html
Package vorbis implements the Go bindings of a subset (only one function) of the functions of the libvorbis library See API reference at: https://xiph.org/vorbis/doc/libvorbis/reference.html
Package camera contains common camera types used for rendering 3D scenes.
Package camera contains common camera types used for rendering 3D scenes.
control
Package control implements controllers for cameras
Package control implements controllers for cameras
Package core implements some basic types used by other packages.
Package core implements some basic types used by other packages.
experimental
physics
Package collision implements collision related algorithms and data structures.
Package collision implements collision related algorithms and data structures.
physics/collision
Package collision implements collision related algorithms and data structures.
Package collision implements collision related algorithms and data structures.
physics/constraint
Package constraint implements physics constraints.
Package constraint implements physics constraints.
physics/equation
Package equation implements SPOOK equations based on the 2007 PhD thesis of Claude Lacoursière titled "Ghosts and Machines: Regularized Variational Methods for Interactive Simulations of Multibodies with Dry Frictional Contacts"
Package equation implements SPOOK equations based on the 2007 PhD thesis of Claude Lacoursière titled "Ghosts and Machines: Regularized Variational Methods for Interactive Simulations of Multibodies with Dry Frictional Contacts"
physics/solver
Package physics implements a basic physics engine.
Package physics implements a basic physics engine.
Package geometry implements several primitive geometry generators.
Package geometry implements several primitive geometry generators.
gls
Package gls implements a loader of OpenGL functions for the platform and a Go binding for selected OpenGL functions.
Package gls implements a loader of OpenGL functions for the platform and a Go binding for selected OpenGL functions.
Package graphic implements scene objects which have a graphic representation.
Package graphic implements scene objects which have a graphic representation.
gui
Package gui implements the GUI infraestructure and several widgets.
Package gui implements the GUI infraestructure and several widgets.
Package light contains common light types which can be add to a 3D scene to illuminate it.
Package light contains common light types which can be add to a 3D scene to illuminate it.
loader
collada
Package collada
Package collada
gltf
Package gltf
Package gltf
obj
Package obj
Package obj
Package material contains several types of materials which can be used to set the appearance of graphic object
Package material contains several types of materials which can be used to set the appearance of graphic object
Package math32 implements basic math functions which operate directly on float32 numbers without casting and contains types of common entities used in 3D Graphics such as vectors, matrices, quaternions and others.
Package math32 implements basic math functions which operate directly on float32 numbers without casting and contains types of common entities used in 3D Graphics such as vectors, matrices, quaternions and others.
Package renderer implements the scene renderer.
Package renderer implements the scene renderer.
shaders
Package shaders contains the several shaders used by the engine
Package shaders contains the several shaders used by the engine
Package text implements text font support.
Package text implements text font support.
Package texture contains several types of textures which can be added to materials.
Package texture contains several types of textures which can be added to materials.
tools
g3nshaders
g3nshaders reads shaders files with ".glsl" extensions and generates a Go file containing strings with the content of these files.
g3nshaders reads shaders files with ".glsl" extensions and generates a Go file containing strings with the content of these files.
util
logger
Package logger implements an hierarchical logger used by other packages.
Package logger implements an hierarchical logger used by other packages.
Package window abstracts the OpenGL Window manager Currently only "glfw" is supported
Package window abstracts the OpenGL Window manager Currently only "glfw" is supported

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